Kingsley Day, long a mainstay performer with the Evanston-based Savoyaires Gilbert and Sullivan theater company, will ply the boards one last time this year in the title role of “Thespis,” for which he wrote the music.

“Thespis” was Gilbert and Sullivan’s first joint effort, premiering in London in 1871. However most of the music was subsequently lost, and later performances have relied on scores by other composers.

Kingsley Day

Mr. Day, an accomplished musician and composer, wrote a piano score in 1982 for a scaled-down revival of “Thespis” in Chicago. Francis Lynch, a regular in the Savoyaires and also an accomplished musician, helped orchestrate the piano score for the company in 2004 in collaboration with Daniel Robinson. Reviewers were delighted. The Chicago Tribune called the music “an inspired substitute in the Sullivan style” and the Chicago Reader gushed, “Operetta fans can die happy now that the Savoyaires have ‘re-created’ Gilbert and Sullivan’s first collaboration.”

This year’s production, the company 52nd since it was founded in 1973 by writer Lilias Circle and Chicago Symphony cellist and Evanston Symphony Music Director Frank Miller, is marked by several other highlights.

The guest director is Dominic Missimi, a two-time Jeff Award winner who founded and formerly led Northwestern University’s Music Theatre Program. Mr. Missimi has directed productions at Chicago Shakespeare Theater, Chicago Opera Theater, Drury Lane Theater, and 36 shows at the Marriott Theater in Lincolnshire.

The set designer is Alan Donahue, a multiple Jeff Award winner. The costume designer is Tom Kieffer, another Jeff winner. And returning for his ninth season as Music Director is Tim Semanik.

In addition, the Savoyaires’ “Thespis” will be the centerpiece of the second Gilbert and Sullivan Summit, a conference of Gilbert and Sullivan companies from across the country.

Mr. Day, first saw the Savoyaires under Mr. Miller’s baton in 1977, shortly after he moved to Chicago from Rochester, New York, where he had finished his master’s degree in music at the Eastman School.

He spent the next few years in the city composing original musicals, and with co-writer Philip LaZebnik “hit the jackpot,” he says, with “Byrne, Baby, Byrne” about Chicago’s reformist Mayor Jane Byrne, which ran for 2½ years.

Another collaboration with Mr. LaZebnik was “Summer Stock Murder,” which ran 18 months at the Theater Building on Belmont and won eight Jeff Awards, including best new work.

Their two-person comedy, “Tour de Farce,” with Chicago favorite Hollis Resnick and a very youthful Steve Carell, premiered in 1992 at the Wisdom Bridge Theater on Howard Street, and subsequently has been produced in theaters around the country and in Europe.

During this time Mr. Day also taught music at Columbia College and wrote and performed in other musicals that were nominated for Jeff Awards.

He says his love of Gilbert and Sullivan operettas began in high school in Columbia, Missouri, where he grew up. In his sophomore year the spring musical was “H.M.S. Pinafore.” “I was only familiar with Broadway-type musicals. My first reaction was, ‘why are they doing this?’ Then I fell in love with it. I was hooked on Gilbert and Sullivan for life.”

At Lawrence University, where he got his Bachelor of Music degree, he produced and directed another Gilbert and Sullivan operetta, “Trial By Jury.”

His first performance with the Savoyaires was in 1998 as Bunthorne in “Patience.” The following year he was cast as the Major General in “Pirates of Penzance” but dropped out to be the music director for “Hello Muddah, Hello Fadduh” at the Apollo Theater, for which he was nominated for a Jeff.

He returned to the Savoyaires in 2000 as Ko-Ko in “The Mikado” and has played major roles almost every year since. His specialty is the “patter song,” a fast-paced number that is a favorite in the Gilbert and Sullivan operettas. (An example is “I am the very model of a modern major general.”) He points out that with “Thespis,” he will have performed the patter baritone role in every one of the 14 Gilbert and Sullivan operettas, which puts him in very select company.

Mr. Day announced some time ago that this year’s performance would be his last with the Savoyaires.

“I’ve had a wonderful run with the company, and to finish up with a show I wrote the music for is very special,” he said. “Plus, I’ve never actually performed in it.” He conceded that “it will probably be a little emotional for me,” but added he still hopes to play an active role with the theater company, just not on stage.

“Nobody I’ve worked with has more integrity, works as hard, or comes as well prepared as Kingsley,” said Mr. Semanik.

“I don’t know how we’re going to replace him,” said Savoyaires’ Board President Kathy Szoke. “He’s wonderful to work with, whether on stage or backstage. He’s a mainstay of the organization.”

Performances will be held on Oct. 7, 8, 14, and 15 at 7:30 p.m.; and Oct. 9 and 16 at 3 p.m. at Chute School, 1400 Oakton St. Tickets range from $12 to $27 and may be purchased by phone at 847-563-0155, online at www.savoyaires.org/tickets and by mail from Savoyaires, P.O. Box 126, Evanston, 60204.